1. Field of the Invention
The present invention relates to a die for a bending flat metal stock and, in particular, a means for controlling the angular orientation of the lower die plate members supporting the metal stock.
2. Description of the Prior Art
A number of prior art flat metal bending dies have been disclosed in the prior art. For example, U.S. Pat. No. 5,060,501 to Heath discloses a flat metal bending die which incorporates two elongated die bars supported for both translational and pivotal movement, the wedge shaped cross-sectional shape of the die bars facilitating the angular bending of flat metal stock without the typical material scoring caused by relative movement between the die bars and the flat metal stock during a bending operation. Although the Heath apparatus disclosed is used to bend stock in a 90 degree bend and it is noted that the die assembly could be modified to bend stock into other angular configurations, it is apparent that significant modifications would be required to accommodate various bending angles.
The concept of using a lower die member having pivotable members, as shown in Heath, in forming metal parts in itself has been known in the prior art for many years. For example, U.S. Pat. No. 240,174 to Pearce, issued on Apr. 12, 1881 discloses a die having pivotable block members secured in a base die the block members moving from an initial first angular orientation to a second orientation as the part is being formed.
Currently, however, there is no sheet metal processing die assembly available whereon the angularly orientation of the V-shaped female die member (lower bending tool), utilized to bend sheet metal into precise angles, can be automatically adjusted in a cost efficient manner. The adjustments are conventionally made by changing the components of the female die member, a costly and labor intensive process.
What is therefore desired is to provide an improved die assembly wherein the angular orientation of the plate members forming the lower die member can be adjusted in a more cost effective manner than has heretofore been available.